Meet Hektor, a Swiss-designed
spraycan graffiti robot, or possibly one of the world's largest portable inkjet printers.
(Note that it's not the largest, as the BBC piece suggests;
I recall a larger version of
GraffitiWriter, one of Hektor's predecessors, mounted on the underside of a van, and used to inscribe dot-matrix slogans on roads.)
Not really a predecessor though, as the Hektor one is to Graffitiwriter as vector is to raster, if you get what I mean